1-20 GHz Directly Modulated Radio over MMF Link

Abstract

Directly modulated multimode-fiber (MMF) based radio-over-fiber links are demonstrated which support RF carrier frequencies up to 20GHz. This is believed to be the highest frequency yet reported for RF signal transmission using a directly modulated laser. The DFB laser diode introduces less than 1% excess EVM up to 16GHz, while both high-and low-bandwidth MMF links introduce very little penalty at carrier frequencies in excess of 20GHz for distances of 1000m and 575m, respectively.Index Terms -Error vector magnitude, microwave communication, optical fiber communication, radio-overfiber (RoF), semiconductor lasers.

Characterisation of Multimode Fibres for Use in Millimetre Wave Radio-Over-Fibre Systems

“…Thus, MMF has been used at much higher data rates and frequencies than had been thought possible. Recently results have been shown as high as 25GHz [10]. It is interesting to postulate what is the maximum frequency to which these passbands extend.…”

“…The 60 GHz band has a specific attenuation characteristic caused by water molecules (rain) and oxygen in the atmosphere i.e. (10)(11)(12)(13)(14)(15) dB/Km at 60 GHz) [2] which means for long-distance (> 2 km) links, many small closely spaced cells with small antennas will be necessary. Coaxial cables also become very lossy at 60GHz and thus optical fibre becomes attractive and is emerging as an ideal medium for the distribution of mmwave signals due to its low loss, low cost, large bandwidth, and immunity to electromagnetic interference characteristics.…”

Phase-modulated radio over fiber multimode links

“…A wide range of contributions, including mode group diversity multiplexing [1], optical frequency multiplication [2], the application of MIMO (Multiple Input Multiple Output) techniques [3], subcarrier multiplexing (SCM) [4], Orthogonal Frequency-Division Multiplexing (OFDM) [5] and wavelength division multiplexing (WDM) [4,6], are trying to accomplish this goal implementing intensity modulated radio over fiber (ROF) transmission with either direct or coherent detection schemes. On the other hand, the use of low linewidth lasers, instead of traditional LED based transmitters, has been demonstrated to support the delivery of ROF signals beyond the typical MMF bandwidth-distance product [7,8] for a range of microwave frequencies up to 20 GHz through MMF links up to 5 km. Actually, the combination of modefiltering solutions implemented by centrally launching the light from a SMF, and low linewidth lasers has shown the capability of reaching broadband transmission, both radio over fibre [7,8] and digital baseband [6,9] transmission, in middle-reach MMF links.…”

Overcoming Modal Bandwidth Limitation in Radio-over-Multimode Fiber Links

“…For the emerging broadband wireless systems operating at carrier frequencies in the microwave/millimeter wave bands, the theoretical modal bandwidth limit imposed by the well-known bandwidth-distance product, confines the use of MMF to very short links. Exploiting the passband transmission region of MMF, microwave signals can be transmitted over MMF links [3], but the passband region differs with fiber length variations, which might not be practical in the rollout of a radio-over-MMF-based infrastructure. Another method to overcome this theoretical bandwidth limitation is the optical frequency multiplication (OFM) principle [4].…”